Terebellum (astronomy)
Encyclopedia
The Terebellum, by Ptolemy
called τετράπλευρον (/tetrápleuron/), is a quadrilateral
of star
s in the constellation
Sagittarius
. It is formed of four 4th magnitude
stars, all within two degrees of each other:
The stars are not gravitationally bound to each other as they are at different distances from the Earth
.
Ptolemy
Claudius Ptolemy , was a Roman citizen of Egypt who wrote in Greek. He was a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in Egypt under Roman rule, and is believed to have been born in the town of Ptolemais Hermiou in the...
called τετράπλευρον (/tetrápleuron/), is a quadrilateral
Quadrilateral
In Euclidean plane geometry, a quadrilateral is a polygon with four sides and four vertices or corners. Sometimes, the term quadrangle is used, by analogy with triangle, and sometimes tetragon for consistency with pentagon , hexagon and so on...
of star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
Sagittarius
Sagittarius (constellation)
Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow...
. It is formed of four 4th magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
stars, all within two degrees of each other:
- Omega SagittariiOmega SagittariiOmega Sagittarii is a G-type subgiant star in the constellation of Sagittarius. It has an apparent visual magnitude of approximately 4.70. It is the northeast corner of the asterism called the Terebellum and at approximately 78 light years from Earth, it is the nearest of the four stars in...
, at the northeast corner. - 59 Sagittarii59 Sagittarii59 Sagittarii , also known by its Bayer designation b Sagittarii, is a K-type bright giant star in the constellation of Sagittarius. It has an apparent visual magnitude of approximately 4.544...
or b Sagittarii, at the southeast corner. - 60 Sagittarii60 Sagittarii60 Sagittarii , or A Sagittarii , is a G-type giant star in the constellation of Sagittarius. It is approximately 340 light-years from the Earth. It is the northwest corner of the asterism called the Terebellum and, with an apparent magnitude of approximately 4.851, it is the dimmest...
or A Sagittarii, at the northwest corner. - 62 Sagittarii62 Sagittarii62 Sagittarii or c Sagittarii is an M-type giant star in the constellation of Sagittarius. It is the southwest corner of the asterism called the Terebellum. It is an irregular variable whose apparent visual magnitude varies between 4.45 and 4.64, and, at its brightest, it is the...
or c Sagittarii, at the southwest corner.
The stars are not gravitationally bound to each other as they are at different distances from the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
.
External links
- Sagittarius in the LacusCurtiusLacusCurtiusLacusCurtius is a website specializing in ancient Rome, currently hosted on a server at the University of Chicago. It went online on August 26, 1997; in January 2008 it had "2786 pages, 690 photos, 675 drawings & engravings, 118 plans, 66 maps." The site is the...
version of Star Names: Their Lore and MeaningStar Names: Their Lore and MeaningStar Names: Their Lore and Meaning is a book by Richard Hinckley Allen, published in 1899.It discusses the names of stars and constellations and their origin.-Author:...
.